Day, a 21-year-old Australian who has shared the lead after all three rounds, turned in a 70 Saturday.
Bradley and Day were at 12-under 204 with a four-stroke lead over eight players.
Brett Quigley, winless in 341 career PGA Tour starts, shot a 69 to lead the pack at eight-under 208. Quigley was joined by Jay Williamson (67), Greg Chalmers (70), Omar Uresti (70), Kent Jones (70), Cliff Kresge (72), Bart Bryant (73) and Bryce Molder (72).
2014: The Year in Fashion [PHOTOS]
LeBron James reveals his new Nike shoes